Such AIs have existed in Brood War and Dota 2 for a very long time now (pre-LLM), problem is they aren't very fun for humans to play against.

with better being more convincing, rather than just stronger

its the same for like a chess bot. i dont want a perfect stockfish that occasionally makes a serious blunder when a dice rolls a certain way. i want one that actually falls into traps

You could play against an AI right now on the Brood War ladder right now. Granted, you have to make it to S rank first because that's where the bots end up.